Question

a ultrasonic wave at 8x10^4 Hz is emitted into a vien where the speed of sound in blood is 1570 m/s. the wave reflects off the red blood cells moving towards the stationary receiver, if the frequency of the4 returning signal is 8.002x10^4 Hz, what is the speed of blood flow?

Answer 1

Answer: 0.392 m/s

Step-by-step explanation:

The Doppler shift equation is:

`f'=(V+V_(o))/(V-V_(s)) f`

Where:

`f=8(10)^(4) Hz` is the actual frequency of the sound wave

`f'=8.002(10)^(4) Hz` is the "observed" frequency

`V=1570 m/s` is the speed of sound

`V_(o)=0 m/s` is the velocity of the observer, which is stationary

`V_(s)` is the velocity of the source, which are the red blood cells

Isolating
`V_(s)`:

`V_(s)=(V(f'-f))/(f')`

`V_(s)=(1570 m/s(8.002(10)^(4) Hz-8(10)^(4) Hz))/(8.002(10)^(4) Hz)`

Finally:

`V_(s)=0.392 m/s`